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context("Download NARR via THREDDS")

start_date <- "2012-02-20"
end_date <- "2012-03-05"
ntime <- as.numeric(difftime(end_date, start_date) + 1) * 24 / 3 + 1
lat.in <- 43.3724
lon.in <- -89.9071

outfolder <- tempfile()
dir.create(outfolder)

# Create a fake NARR file the outfolder against which we will test
testfile <- file.path(outfolder, "_dl_narr_test.nc")
time_units <- "hours since 2012-02-20"
time_vals <- seq_len(difftime(end_date, start_date, units = "hours") * 3) - 1
timedim <- ncdf4::ncdim_def("time", units = time_units, vals = time_vals)
reftimedim <- ncdf4::ncdim_def("reftime", units = time_units, vals = time_vals)
flx_vars <- purrr::pmap(list(
  name = narr_flx_vars[["NARR_name"]],
  units = narr_flx_vars[["units"]]
), ncdf4::ncvar_def, dim = timedim)
sfc_vars <- purrr::pmap(list(
  name = narr_sfc_vars[["NARR_name"]],
  units = narr_sfc_vars[["units"]]
), ncdf4::ncvar_def, dim = reftimedim)
ncdf4::nc_create(testfile, c(flx_vars, sfc_vars))
nc <- ncdf4::nc_open(testfile, write = TRUE)
purrr::walk(
  flx_vars,
  ncdf4::ncvar_put,
  nc = nc,
  vals = rexp(length(time_vals))
)
purrr::walk(
  sfc_vars,
  ncdf4::ncvar_put,
  nc = nc,
  vals = rexp(length(time_vals))
)

teardown({
  ncdf4::nc_close(nc)
  unlink(outfolder, recursive = TRUE, force = TRUE)
})

test_that(
  "NARR download works as expected",
  {

    # Instead of reading the target NARR file, we read the testfile.
    # This works because the NARR site code only uses nc_open to read
    # the remote file, never to read anything downloaded.
    r <- with_mock(
      "ncdf4::nc_open" = function(filename) ncdf4::nc_open(testfile),
      download.NARR_site(outfolder, start_date, end_date, lat.in, lon.in,
                         progress = FALSE, parallel = FALSE)
    )


    expect_equal(nrow(r), 1)
    expect_true(file.exists(r$file[1]))
    nc <- ncdf4::nc_open(r$file)
    temp <- ncdf4::ncvar_get(nc, "air_temperature")
    precip <- ncdf4::ncvar_get(nc, "precipitation_flux")
    expect_true(all(!is.na(temp)), all(temp > 0), length(temp) == ntime)
    expect_true(all(!is.na(precip)), length(precip) == ntime)
    ncdf4::nc_close(nc)
  }
)